Methods for Alzheimer&#39;s disease treatment and cognitive enhance

ABSTRACT

The present invention relates to compositions comprising a combination of PKC activators and PKC inhibitors and methods to modulate α-secretase activity; improve or enhance cognitive ability; and/or reduce neurodegeneration in individuals suffering from diseases that impair cognitive ability, particularly Alzheimer&#39;s Disease. The invention also relates to methods for improving or enhancing cognitive ability. The present invention also provides methods for increasing the generation of non-amyloidogenic soluble APP (sAPP) comprising the activation of protein kinase C (PKC) in the brain and inhibiting PKC in peripheral tissues. Macrocyclic lactones (i.e. bryostatin class and neristatin class) are preferred PKC activators and Vitamin E is a preferred PKC inhibitor for use in the inventive composition.

This application is a continuation-in-part application of U.S.Non-Provisional application Ser. No. 10/167,491, filed on Jun. 13, 2002,which claims priority to U.S. Provisional Application No. 60/362,080,filed on Mar. 7, 2002.

FIELD OF THE INVENTION

The present invention relates to the modulation of a-secretase and tocognitive enhancement. The invention further relates to compounds fortreatment of conditions associated with amyloid processing such asAlzheimer's Disease and compositions for the treatment of suchconditions.

BACKGROUND OF THE INVENTION

Various disorders and diseases exist which affect cognition. Cognitioncan be generally described as including at least three differentcomponents: attention, learning, and memory. Each of these componentsand their respective levels affect the overall level of a subject'scognitive ability. For instance, while Alzheimer's Disease patientssuffer from a loss of overall cognition and thus deterioration of eachof these characteristics, it is the loss of memory that is most oftenassociated with the disease. In other diseases patients suffer fromcognitive impairment that is more predominately associated withdifferent characteristics of cognition. For instance Attention DeficitHyperactivity Disorder (ADHD), focuses on the individual's ability tomaintain an attentive state. Other conditions include general dementiasassociated with other neurological diseases, aging, and treatment ofconditions that can cause deleterious effects on mental capacity, suchas cancer treatments, stroke/ischemia, and mental retardation.

Cognition disorders create a variety of problems for today's society.Therefore, scientists have made efforts to develop cognitive enhancersor cognition activators. The cognition enhancers or activators that havebeen developed are generally classified to include nootropics,vasodilators, metabolic enhancers, psychostimulants, cholinergic agents,biogenic amine drugs, and neuropeptides. Vasodilators and metabolicenhancers (e.g. dihydroergotoxine) are mainly effective in the cognitiondisorders induced by cerebral vessel ligation-ischemia; however, theyare ineffective in clinical use and with other types of cognitiondisorders. Of the developed cognition enhancers, typically onlymetabolic drugs are employed for clinical use, as others are still inthe investigation stage. Of the nootropics for instance, piracetamactivates the peripheral endocrine system, which is not appropriate forAlzheimer's disease due to the high concentration of steroids producedin patients while tacrine, a cholinergic agent, has a variety of sideeffects including vomiting, diarrhea, and hepatotoxicity.

Identifying means for improving the cognitive abilities of diseasedindividuals has been the goal of several studies. Recently the cognitivestate related to Alzheimer's Disease and different methods to improvememory have been the subject of various approaches and strategies,which, unfortunately, have only improved symptomatic and transientcognition in diseased individuals and have not addressed the progressionof the disease. In the case of Alzheimer's Disease, efforts to improvecognition, typically through the cholinergic pathways or through otherbrain transmitter pathways, have been investigated. The primary approachrelies on the inhibition of acetyl cholinesterase enzymes through drugtherapy. Acetyl cholinesterase is a major brain enzyme and manipulatingits levels can result in various changes to other neurological functionsand cause side effects.

While these and other methods may improve cognition, at leasttransiently, they do not modify the disease progression, or address thecause of the disease. For instance, Alzheimer's Disease is typicallyassociated with the formation of plaques through the accumulation ofamyloid precursor protein. Attempts to illicit an immunological responsethrough treatment against amyloid and plaque formation have been done inanimal models, but have not been successfully extended to humans.

Furthermore, cholinesterase inhibitors only produce some symptomaticimprovement for a short time and in only a fraction of the Alzheimer'sDisease patients with mid to moderate symptoms and are thus only auseful treatment for a small portion of the overall patient population.Even more critical is that present efforts at improving cognition do notresult in treatment of the disease condition, but are merelyameliorative of the symptoms. Current treatments do not modify thedisease progression. These treatments have also included the use of a“vaccine” to treat the symptoms of Alzheimer's Disease patients which,while theoretically plausible and effective in mice tests, have beenshown to cause severe adverse reactions in humans.

As a result, use of the cholinergic pathway for the treatment ofcognitive impairment, particularly in Alzheimer's Disease, has proven tobe inadequate. Additionally, the current treatments for cognitiveimprovement are limited to specific neurodegenerative diseases and havenot proven effective in the treatment of other cognitive conditions.

Alzheimer's disease is associated with extensive loss of specificneuronal subpopulations in the brain with memory loss being the mostuniversal symptom. (Katzman, R. (1986)) New England Journal of Medicine314:964). Alzheimer's disease is well characterized with regard toneuropathological changes. However, abnormalities have been reported inperipheral tissue supporting the possibility that Alzheimer's disease isa systematic disorder with pathology of the central nervous system beingthe most prominent. (Connolly, G., Fibroblast models of neurologicaldisorders: fluorescence measurement studies, Review, TiPS Col. 19,171-77 (1998)). For a discussion of Alzheimer's disease links to agenetic origin and chromosomes 1, 14, and 21 see St. George-Hyslop, P.H., et al., Science 235:885 (1987); Tanzi, Rudolph et al., The GeneDefects Responsible for Familial Alzheimer's Disease, Review,Neurobiology of Disease 3, 159-168 (1996); Hardy, J., Molecular geneticsof Alzheimer's disease, Acta Neurol Scand: Supplement 165: 13-17 (1996).

While cellular changes leading to neuronal loss and the underlyingetiology of the disease remain under investigation, the importance ofAPP metabolism is well established. The two proteins most consistentlyidentified in the brains of patients with Alzheimer's disease to play arole in the physiology or pathophysiology of brain are β-amyloid andtau. (See Selkoe, D., Alzheimer's Disease: Genes, Proteins, and Therapy,Physiological Reviews, Vol. 81, No. 2, 2001). A discussion of thedefects in β-amyloid protein metabolism and abnormal calcium homeostasisand/or calcium activated kinases. (Etcheberrigaray et al., Calciumresponses are altered in fibroblasts from Alzheimer's patients andpresymptomatic PS1 carriers: a potential tool for early diagnosis,Alzheimer's Reports, Vol. 3, Nos. 5 & 6, pp. 305-312 (2000); Webb etal., Protein kinase C isozymes: a review of their structure, regulationand role in regulating airways smooth muscle tone and mitogenesis,British Journal of Pharmacology, 130, pp. 1433-52 (2000)).

Both K⁺ and Ca²⁺ channels have been demonstrated to play key roles inmemory storage and recall. For instance, potassium channels have beenfound to change during memory storage. (Etcheberrigaray, R., et al.(1992) Proceeding of the National Academy of Science 89:7184;Sanchez-Andres, J. V. and Alkon, D. L. (1991) Journal of Neurobiology65:796; Collin, C., et al. (1988) Biophysics Journal 55:955; Alkon; D.L., et al. (1985) Behavioral and Neural Biology 44:278; Alkon, D. L.(1984) Science 226:1037). This observation, coupled with the almostuniversal symptom of memory loss in Alzheimer's patents, led to theinvestigation of potassium channel function as a possible site ofAlzheimer's disease pathology and the effect of PKC modulation oncognition.

PKC was identified as one of the largest gene families of non-receptorserine-threonine protein kinases. Since the discovery of PKC in theearly eighties by Nishizuka and coworkers (Kikkawa et al., J. Biol.Chem., 257, 13341 (1982), and its identification as a major receptor ofphorbol esters (Ashendel et al., Cancer Res., 43, 4333 (1983)), amultitude of physiological signaling mechanisms have been ascribed tothis enzyme. The intense interest in PKC stems from its unique abilityto be activated in vitro by calcium and diacylglycerol (and its phorbolester mimetics), an effector whose formation is coupled to phospholipidturnover by the action of growth and differentiation factors.

The PKC gene family consists presently of 11 genes which are dividedinto four subgrounds: 1) classical PKCα, β₁, β₂ (β₁ and β₂ arealternatively spliced forms of the same gene) and γ, 2) novel PKCδ, ε, ηand θ, 3) atypical PKCζ, λ, η and ι and 4) PKCμ. PKCμ resembles thenovel PKC isoforms but differs by having a putative transmembrane domain(reviewed by Blohe et al., Cancer Metast. Rev. 13, 411 (1994); Ilug etal., Biochem j., 291, 329 (1993); Kikkawa et al., Ann. Rev. Biochem. 58,31 (1989)). The α, β₁, β₂, and γ isoforms are Ca², phospholipid anddiacylglycerol-dependent and represent the classical isoforms of PKC,whereas the other isoforms are activated by phospholipid anddiacylglycerol but are not dependent on CA²⁺. All isoforms encompass 5variable (V1-V5) regions, and the α, β, γ isoforms contain four (C1-C4)structural domains which are highly conserved. All isoforms except PKCα,β and γ lack the C2 domain, and the λ, η and isoforms also lack nine oftwo cysteine-rich zinc finger domains in C1 to which diacylglycerolbinds. The C1 domain also contains the pseudosubstrate sequence which ishighly conserved among all isoforms, and which serves an autoregulatoryfunction by blocking the substrate-binding site to produce an inactiveconformation of the enzyme (House et al., Science, 238, 1726 (1987)).

Because of these structural features, diverse PKC isoforms are thoughtto have highly specialized roles in signal transduction in response tophysiological stimuli (Nishizuka, Cancer, 10, 1892 (1989)), as well asin neoplastic transformation and differentiation (Glazer, Protein KinaseC. J. F. Kuo, ed., Oxford U. Press (1994) at pages 171-198). For adiscussion of known PKC modulators, see: PCT/US97/08141, U.S. Pat. Nos.5,652,232; 6,043,270; 6,080,784; 5,891,906; 5,962,498; 5,955,501;5,891,870 and 5,962,504 (each of which is incorporated herein byreference in its entirety).

In view of the central role that PKC plays in signal transduction, PKChas proven to be an exciting target for the modulation of APPprocessing. It is well established that PKC plays a role in APPprocessing. Phorbol esters for instance have been shown to significantlyincrease the relative amount of non-amyloidogenic soluble APP (sAPP)secreted through PKC activation. Activation of PKC by phorbol ester doesnot appear to result in a direct phosphorylation of the APP molecule,however. Irrespective of the precise site of action, phorbol-induced PKCactivation results in an enhanced or favored α-secretase,non-amyloidogenic pathway. Therefore PKC activation is an attractiveapproach for influencing the production of non-deleterious sAPP and evenproducing beneficial sAPP and at the same time reduce the relativeamount of Aβ peptides. Phorbol esters, however, are not suitablecompounds for eventual drug development because of their tumor promotionactivity. (Ibarreta et al. (1999) Benzolactam (BL) enhances sAPPsecretion in fibroblasts and in PC12 cells, NeuroReport 10(5&6):1034-40; incorporated herein by reference in its entirety).

There is increasing evidence that the individual PKC isozymes playdifferent, sometimes opposing, roles in biological processes, providingtwo directions for pharmacological exploitation. One is the design ofspecific (preferably, isozyme specific) inhibitors of PKC. This approachis complicated by the fact that the catalytic domain is not the domainprimarily responsible for the isotype specificity of PKC. The otherapproach is to develop isozyme-selective, regulatory site-directed PKCactivators. These may provide a way to override the effect of othersignal transduction pathways with opposite biological effects.Alternatively, by inducing down-regulation of PKC after acuteactivation, PKC activators may cause long term antagonism. Bryostatin iscurrently in clinical trials as an anti-cancer agent. The bryostatinsare known to bind to the regulatory domain of PKC and to activate theenzyme. Bryostatin is an example of isozyme-selective activators of PKC.Compounds in addition to bryostatins have been found to modulate PKC.(See, for example, WO 97/43268; incorporated herein by reference in itsentirety).

There still exists a need for the development of methods for thetreatment for improved overall cognition, either through a specificcharacteristic of cognitive ability or general cognition. There alsostill exists a need for the development of methods for the improvementof cognitive enhancement whether or not it is related to specificdisease state or cognitive disorder. The methods and compositions of thepresent invention fulfill these needs and will greatly improve theclinical treatment for Alzheimer's disease and other neurodegenerativediseases, as well as, provide for improved cognitive enhancement. Themethods and compositions also provide treatment and/or enhancement ofthe cognitive state through the modulation of a-secretase.

SUMMARY OF THE INVENTION

The invention relates to compounds, compositions, and methods for thetreatment of conditions associated with enhancement/improvement ofcognitive ability. In a preferred embodiment, the present inventionfurther relates to compounds, compositions and methods for the treatmentof conditions associated with amyloid processing, such as Alzheimer'sDisease, which provides for improved/enhanced cognitive ability in thesubject treated. In particular the compounds and compositions of thepresent invention are selected from macrocyclic lactones (i.e.bryostatin and neristatin class).

Another aspect of the invention relates to macrocyclic lactonecompounds, compositions and methods that modulate a-secretase activity.Of particular interest are the bryostatin and neristatin classcompounds, and of further interest is bryostatin-1.

Another aspect of the invention relates to the bryostatin and neristatinclass compounds, as a PKC activator, to alter conditions associated withamyloid processing in order to enhance the α-secretase pathway togenerate soluble α-amyloid precursor protein (αAPP) so as to preventβ-amyloid aggregation and improve/enhance cognitive ability. Suchactivation, for example, can be employed in the treatment of Alzheimer'sDisease. Of particular interest is bryostatin-1.

In another aspect, the invention relates to a method for treating plaqueformation, such as that associated with Alzheimer's Disease, andimproving/enhancing the cognitive state of the subject comprisingadministering to the subject an effective amount of macrocyclic lactoneto activate PKC. In a preferred embodiment, the PKC activator is of thebryostatin or neristatin class of compounds. In a more preferredembodiment the compound is bryostatin-1.

Another aspect of the invention relates to a composition for treatingplaque formation and improving/enhancing cognitive ability comprising:(i) a macrocyclic lactone in an amount effective to elevate solubleβ-amyloid, generate soluble αAPP and prevent β-amyloid aggregation; and(ii) a pharmaceutically effective carrier. In a preferred embodiment thecomposition is used to improve/enhance cognitive ability associated withAlzheimer's Disease. The macrocyclic lactone is preferably selected fromthe bryostatin or neristatin class compounds, particularly bryostatin-1.

In one embodiment of the invention the activation of PKC isoenzymesresults in improved cognitive abilities. In one embodiment the improvedcognitive ability is memory. In another embodiment the improvedcognitive ability is learning. In another embodiment the improvedcognitive ability is attention. In another embodiment PKC's isoenzymesare activated by a macrocyclic lactone (i.e. bryostatin class andneristatin class). In particular, bryostatin-1 through 18 and neristatinis used to activate the PKC isoenzyme. In a preferred embodimentbryostatin-1 is used.

In another aspect, the invention comprises a composition of PKCisoenzyme activator administered in a amount effective to improvecognitive abilities. In a preferred embodiment the PKC isoenzymeactivator is selected from macrocyclic lactones (i.e. bryostatin classand neristatin class). In a preferred embodiment the amount of PKCactivator administered is in an amount effective to increase theproduction of sAPP. In a more preferred embodiment the amount ofcomposition administered does not cause myalgia.

In a preferred embodiment the PKC isoenzymes are activated in subjects,which are suffering or have suffered from neurological diseases, strokesor hypoxia. In a more preferred embodiment the PKC isoenzyme isactivated in Alzheimer's Disease subjects or models.

In another embodiment of the invention the PKC activation results in themodulation of amyloid precursor protein metabolism. Further themodulation by the PKC activation results in an increase in the alphasecretase pathway. The alpha secretase pathway results in non-toxic,non-amyloidogenic fragments related to cognitive impairment. As a resultthe cognitive condition of the subject improves. In another embodimentof the invention the PKC activation reduces the amyloidogenic and toxicfragments Abeta 40 and Ab42.

Another embodiment of the invention is a method of improving cognitiveability through the activation of PKC isoenzymes. In another embodimentof the invention the PKC activation occurs in “normal” subjects. Inanother embodiment of the invention the PKC activation occurs insubjects suffering from a disease, deteriorating cognitive faculties, ormalfunctioning cognition. In a preferred embodiment the method is amethod for treating Alzheimer's Disease.

In another embodiment of the invention the modulation of PKC is throughthe use of a non-tumor promoting agent resulting in improved cognitiveabilities. In a preferred embodiment the PKC activator is selected frombryostatin-1 through bryostatin-18 and neristatin. In a more preferredembodiment bryostatin-1 is used. In another embodiment bryostatin-1 isused in combination with a non-bryostatin class compound to improvecognitive ability and reduce side effects.

In another embodiment of the invention, the modulation of PKC throughmacrocyclic lactones (i.e. bryostatin class and neristatin class) isused in vitro for the testing of conditions associated with Alzheimer'sDisease. The in vitro use may include for example, the testing offibroblast cells, blood cells, or the monitoring of ion channelconductance in cellular models.

In a preferred embodiment of the invention the compounds andcompositions are administered through oral and/or injectable formsincluding intravenously and intraventricularly.

The present invention therefore provides a method of treating impairedmemory or a learning disorder in a subject, the method comprisingadministering thereto a therapeutically effective amount of one of thepresent compounds. The present compounds can thus be used in thetherapeutic treatment of clinical conditions in which memory defects orimpaired learning occur. In this way memory and learning can beimproved. The condition of the subject can thereby be improved.

The present invention also provides methods for the treatment ofconditions associated with amyloid processing. In one embodiment, themethods for treatment of conditions associated with amyloid processingcomprise the administration of any of the compositions of the presentinvention that comprise a PKC activator and a PKC inhibitor. Preferably,the administered composition produces only moderate myalgia in themajority of patients treated with said composition. More preferably, theadministered composition does not produce myalgia in the majority ofpatients treated with said composition.

In another embodiment, the methods of the present invention comprise thesteps of administering to a subject in need thereof: a) a PKC activatorwith or without a pharmaceutically acceptable carrier and b) a PKCinhibitor with or without a pharmaceutically acceptable carrier. In oneembodiment, the PKC activator is administered in an amount effective toenhance or improve cognitive ability. In another embodiment, the PKCactivator is administered in an amount effective to increase(x-secretase activity. In another embodiment, the PKC activator isadministered in an amount effective to reduce the loss of cognitiveability a subject in need thereof. Preferably, the cognitive ability isselected from the group consisting of learning, memory and attention. Inyet another embodiment, the PKC activator is administered in an amounteffective to increase the production of sAPP.

In one embodiment, the PKC activator is administered in an amounteffective to reduce neurodegeneration in a subject in need thereof.Preferably, the subject in need thereof suffers from a neurodegenerativedisease selected from the group consisting of Alzheimer's Disease;multi-infarct dementia; the Lewy-body variant of Alzheimer's Diseasewith or without association with Parkinson's disease; Creutzfeld-Jakobdisease; Korsakoff's disorder; and attention deficit hyperactivitydisorder. Most preferably, the neurodegenerative disease is Alzheimer'sDisease.

In the methods of the present invention, the PKC activator is preferablyselected from the group consisting of a macrocyclic lactone,benzolactam, a pyrrolidinone and a combination thereof. In oneembodiment, the PKC activator increases the production of sAPP. Inanother embodiment, the PKC activators of the present invention arenon-tumorigenic. In a preferred embodiment, the PKC activator is apyrrolidinone. In a more preferred embodiment, the PKC activator is abenzolactam. In the most preferred embodiment, the PKC activator is amacrocyclic lactone. Preferably, the macrocyclic lactone selected from agroup consisting of bryostatin- and neristatin-class compounds. In apreferred embodiment of the present invention, the macrocyclic lactoneis neristatin-1. In a more preferred embodiment, the macrocyclic lactoneis selected from the group consisting of bryostatin-1, -2, -3, -4, -5,-6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16, -17, and -18. Mostpreferably, the macrocyclic lactone is bryostatin-1.

In the methods of the present invention, the PKC inhibitor is a compoundthat inhibits PKC in peripheral tissues. As used herein, “peripheraltissues” means tissues other than brain. In another embodiment, the PKCinhibitor is a compound that preferentially inhibits PKC in peripheraltissues. In another embodiment, the PKC inhibitor is a compound thatreduces myalgia associated with the administration of a PKC activator tosubjects in need thereof. In another embodiment, the PKC inhibitor is acompound that reduces myalgia produced in a subject treated with a PKCactivator. In another embodiment, the PKC inhibitor is a compound thatincreases the tolerable dose of a PKC activator. Specifically, PKCinhibitors include, for example, but are not limited to vitamin E,vitamin E analogs, and salts thereof; calphostin C; thiazolidinediones;ruboxistaurin; and combinations thereof. As used herein, “vitamin E”means α-tocopherol (5,7,8-trimethyltocol); β-tocopherol(5,8-dimethyltocol; δ-tocopherol (8-methyltocol); and γ-tocopherol(7,8-dimethyltocol), salts and analogs thereof.

In the methods of the present invention, the PKC activator is preferablyadministered prior to administration of the PKC inhibitor. Morepreferably, the PKC inhibitor is administered prior to the PKCactivator. Most preferably, the PKC activator and PKC inhibitor areadministered simultaneously.

In a preferred embodiment, the PKC inhibitor is vitamin E. Preferably,the vitamin E is administered in a dose between 15 and 2,000 IU per day;more preferably between 150 and 2,000 IU per day; and most preferablybetween 300 and 2,000 IU per day. As used herein, “one InternationalUnit” or “IU” means the vitamin E activity of one milligram ofdl-α-tocopherol acetate.

The compositions and methods have utility in treating clinicalconditions and disorders in which impaired memory or a learning disorderoccurs, either as a central feature or as an associated symptom.Examples such conditions which the present compounds can be used totreat include Alzheimer's disease, multi-infarct dementia and theLewy-body variant of Alzheimer's disease with or without associationwith Parkinson's disease; Creutzfeld-Jakob disease and Korsakoff'sdisorder.

The compositions and methods can also be used to treat impaired memoryor learning which is age-associated, is consequent uponelectro-convulsive therapy or which is the result of brain damagecaused, for example, by stroke, an anesthetic accident, head trauma,hypoglycemia, carbon monoxide poisoning, lithium intoxication or avitamin deficiency.

The compounds have the added advantage of being non-tumor promoting andalready being involved in phase II clinical trials.

The invention relates to a pharmaceutical composition for enhancingcognition, preventing and/or treating cognition disorders. Moreparticularly, it relates to the pharmaceutical composition comprisingmacrocyclic lactones (i.e. bryostatin class and neristatin class) andtheir derivatives as the active ingredient for enhancing cognition,preventing and/or treating cognition disorders.

It is therefore a primary object of the invention to providepharmaceutical compositions for enhancing cognition, preventing and/ortreating cognition disorders. The pharmaceutical composition comprisesmacrocyclic lactones, particularly the bryostatin and neristatin class,or a pharmaceutically acceptable salt or derivative thereof, and apharmaceutically acceptable carrier or excipient.

The pharmaceutical composition according to the invention is useful inthe enhancement of cognition, prophylaxis and/or treatment of cognitiondisorders, wherein cognition disorders include, but are not limited to,disorders of learning acquisition, memory consolidation, and retrieval,as described herein.

The present invention provides compositions comprising a PKC activatorselected from the group consisting of a macrocyclic lactone,benzolactam, a pyrrolidinone and a combination thereof; a PKC inhibitor;and a pharmaceutically acceptable carrier. In one embodiment, the PKCactivator increases the production of sAPP. In another embodiment, thePKC activators of the present invention are non-tumorigenic. In apreferred embodiment, the PKC activator is a benzolactam. In a morepreferred embodiment, the PKC activator is a pyrrolidinone. In the mostpreferred embodiment, the PKC activator is a macrocyclic lactone.

The present invention also provides compositions comprising amacrocyclic lactone selected from a group consisting of bryostatin- andneristatin-class compounds; a PKC inhibitor; and a pharmaceuticallyacceptable carrier. In one embodiment, the macrocyclic lactone is aneristatin-class compound. In another embodiment, the macrocycliclactone is a bryostatin-class composing. In a preferred embodiment, themacrocyclic lactone is selected from the group consisting ofbryostatin-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14,-15, -16, -17, and -18. In a more preferred embodiment of the presentinvention, the macrocyclic lactone is neristatin-1. In the mostpreferred embodiment, the macrocyclic lactone is bryostatin-1.

In a preferred embodiment, bryostatin-1 is administered in a dose ofbetween 5 and 200 μg/m². In a more preferred embodiment, bryostatin-1 isadministered in a dose of between 10 and 100 μg/m². In a most preferredembodiment, bryostatin-1 is administered in a dose of between 5 and 50μg/m².

In one embodiment, the PKC inhibitor is a compound that inhibits PKC inperipheral tissues. As used herein, “peripheral tissues” means tissuesother than brain. In another embodiment, the PKC inhibitor is a compoundthat preferentially inhibits PKC in peripheral tissues. In anotherembodiment, the PKC inhibitor is a compound that reduces myalgiaassociated with the administration of a PKC activator to subjects inneed thereof. In another embodiment, the PKC inhibitor is a compoundthat reduces myalgia produced in a subject treated with a PKC activator.In another embodiment, the PKC inhibitor is a compound that increasesthe tolerable dose of a PKC activator. In a preferred embodiment, thePKC inhibitor is vitamin E. In a more preferred embodiment, the vitaminE is α-tocopherol.

The invention concerns a method for the treatment of amyloidosisassociated with neurological diseases, including Alzheimer's disease byadministering to a patient an effective amount of at least one agentthat modulates or affects the phosphorylation of proteins in mammaliancells.

The invention also provides a method for treating Alzheimer's diseasecomprising administering to a patient an effective amount of amacrocyclic lactone (i.e. bryostatin class and neristatin class).

In another embodiment the bryostatin or neristatin class compounds maybe used in the above methods in combination with different phorbolesters to prevent or reduce tumorogenic response in the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the effect of different PKC inhibitors on sAPPα secretionwith Bryostatin-I showing greater efficacy at lower concentrations thancontrols and Benzolactam.

FIG. 2 depicts the effect of different concentrations of Bryostatin-1 onthe PKCα isozyme.

FIG. 3 depicts the effect of different concentrations of Bryostatin-1 onsAPPα secretion.

FIG. 4 depicts the amount of time required for treated rats versuscontrols to learn a water maze.

FIG. 5 depicts the observed effect of bryostatin on rat performance inthe water maze: (a) the amount of time control rats spent swimming inthe different quadrants of the water maze; (b) the amount of timetreated rats spent swimming in the different quadrants of the watermaze; and (c) the difference between the amount of time the treated ratsspent in target quadrant of the water maze compared to control rats.

FIG. 6 depicts sAPPα secretion in human fibroblast cells followingadministration of bryostatin (0.1 nM) for both controls and AD cells.

FIG. 7 depicts an immunoblot for sAPP following administration ofbryostatin in AD cells.

DETAILED DESCRIPTION OF THE INVENTION

Memory loss and impaired learning ability are features of a range ofclinical conditions. For instance, loss of memory is the most commonsymptom of dementia states including Alzheimer's disease. Memory defectsalso occur with other kinds of dementia such as multi-infarct dementia(MID), a senile dementia caused by cerebrovascular deficiency, and theLewy-body variant of Alzheimer's disease with or without associationwith Parkinson's disease, or Creutzfeld-Jakob disease. Loss of memory isa common feature of brain-damaged patients. Brain damage may occur, forexample, after a classical stroke or as a result of an anestheticaccident, head trauma, hypoglycemia, carbon monoxide poisoning, lithiumintoxication, vitamin (B1, thiamine and B12) deficiency, or excessivealcohol use or Korsakoff's disorder. Memory impairment may furthermorebe age-associated; the ability to recall information such as names,places and words seems to decrease with increase age. Transient memoryloss may also occur in patients, suffering from a major depressivedisorder, after electro-convulsive therapy (ECT). Alzheimer's disease isin fact the most important clinical entity responsible for progressivedementia in ageing populations, whereas hypoxia/stroke is responsiblefor significant memory defects not related to neurological disorders.

Individuals with Alzheimer's disease are characterized by progressivememory impairments, loss of language and visuospatial skills andbehavior deficits (McKhann et al., 1986, Neurology, 34:939-944). Thecognitive impairment of individuals with Alzheimer's disease is theresult of degeneration of neuronal cells located in the cerebral cortex,hippocampus, basal forebrain and other brain regions. Histologicanalyzes of Alzheimer's disease brains obtained at autopsy demonstratedthe presence of neurofibrillary tangles (NFT) in perikarya and axons ofdegenerating neurons, extracellular neuritic (senile) plaques, andamyloid plaques inside and around some blood vessels of affected brainregions. Neurofibrillary tangles are abnormal filamentous structurescontaining fibers (about 10 nm in diameter) that are paired in a helicalfashion, therefore also called paired helical filaments. Neuriticplaques are located at degenerating nerve terminals (both axonal anddendritic), and contain a core compound of amyloid protein fibers. Insummary, Alzheimer's disease is characterized by certainneuropathological features including intracellular neurofibrillarytangles, primarily composed of cytoskeletal proteins, and extracellularparenchymal and cerebrosvascular amyloid. Further, there are now methodsin the art of distinguishing between Alzheimer's patents, normal agedpeople, and people suffering from other neurodegenerative diseases, suchas Parkinson's, Huntington's chorea, Wernicke-Korsakoff or schizophreniafurther described for instance in U.S. Pat. No. 5,580,748 and U.S. Pat.No. 6,080,582.

Alzheimer's disease (AD) is a brain disorder characterized by alteredprotein catabolism. Altered protein phosphorylation has been implicatedin the formation of the intracellular neurofibrillary tangles found inAlzheimer's disease. A role for protein phosphorylation in thecatabolism of the amyloid precursor protein (APP), from which is derivedthe major component of amyloid plaques found in AD, has also beeninvestigated. A central feature of the pathology of Alzheimer's diseaseis the deposition of amyloid protein within plaques.

The processing of the amyloid precursor protein (APP) determines theproduction of fragments that later aggregate forming the amyloiddeposits characteristic of Alzheimer's disease (AD), known as senile orAD plaques. Thus, APP processing is an early and key pathophysiologicalevent in AD.

Three alternative APP processing pathways have been identified. Thepreviously termed “normal” processing involves the participation of anenzyme that cleaves APP within the AP sequence at residue Lys16 (orbetween Lys16 and Leu17; APP770 nomenclature), resulting innon-amyloidogenic fragments: a large N-terminus ectodomain and a small 9kDa membrane bound fragment. This enzyme, yet to be fully identified, isknown as α-secretase. Two additional secretases participate in APPprocessing. One alternative pathway involves the cleavage of APP outsidethe Aβ domain, between Met671 and Asp672 (by β-secretase) and theparticipation of the endosomal-lysomal system. An additional cleavagesite occurs at the carboxyl-terminal end of the Aβ portion, within theplasma membrane after amino acid 39 of the Aβ peptide. The secretase (γ)action produces an extracellular amino acid terminal that contains theentire Aβ sequence and a cell-associated fragment of ˜6 kDa. Thus,processing by β and γ secretases generate potential amyloidogenicfragments since they contain the complete Aβ sequence. Several lines ofevidence have shown that all alternative pathways occur in a givensystem and that soluble Aβ may be a “normal product.” However, there isalso evidence that the amount of circulating Aβ in CSF and plasma iselevated in patients carrying the “Swedish” mutation. Moreover, culturedcells transfected with this mutation or the APP₇₁₇ mutation, secretelarger amounts of Aβ. More recently, carriers of other APP mutations andPS1 and PS2 mutations have been shown to secrete elevated amounts of aparticular form, long (42-43 amino acids) Aβ.

Therefore, although all alternative pathways may occur normally, animbalance favoring amyloidogenic processing occurs in familial andperhaps sporadic AD. These enhanced amyloidogenic pathways ultimatelylead to fibril and plaque formation in the brains of AD patients. Thus,intervention to favor the non-amyloidogenic, a-secretase pathwayeffectively shifts the balance of APP processing towards a presumablynon-pathogenic process that increases the relative amount of sAPPcompared with the potentially toxic Aβ peptides.

The PKC isoenzymes provides a critical, specific and rate limitingmolecular target through which a unique correlation of biochemical,biophysical, and behavioral efficacy can be demonstrated and applied tosubjects to improve cognitive ability.

The present inventors have studied bryostatins as activators of proteinkinase (PKC). Alterations in PKC, as well alterations in calciumregulation and potassium (K⁺) channels are included among alterations infibroblasts in Alzheimer's disease (AD) patients. PKC activation hasbeen shown to restore normal K⁺ channel function, as measured byTEA-induced [Ca²⁺] elevations. Further patch-clamp data substantiatesthe effect of PKC activators on restoration of 113 psK⁺ channelactivity. Thus PKC activator-based restoration of K⁺ channels has beenestablished as an approach to the investigation of AD pathophysiology,and provides a useful model for AD therapeutics. (See, pending U.S.application Ser. No. 09/652,656, which is incorporated herein byreference in its entirety.)

The use of peripheral tissues from Alzheimer's disease (AD) patients andanimal neuronal cells permitted the identification of a number ofcellular/molecular alterations reflecting comparable processes in the ADbrain and thus, of pathophysiological relevance (Baker et al., 1988;Scott, 1993; Huang, 1994; Scheuner et al., 1996; Etcheberrigaray &Alkon, 1997; Gasparini et al., 1997). Alteration of potassium channelfunction has been identified in fibroblasts (Etcheberrigaray et al.,1993) and in blood cells (Bondy et al., 1996) obtained from AD patients.In addition, it was shown that β-amyloid, widely accepted as a majorplayer in AD pathophysiology (Gandy & Greengard, 1994; Selkoe, 1994;Yankner, 1996), was capable of inducing an AD-like K⁺ channel alterationin control fibroblasts (Etcheberrigaray et al., 1994). Similar orcomparable effects of β-amyloid on K⁺ channels have been reported inneurons from laboratory animals (Good et al., 1996; also for a reviewsee Fraser et al., 1997). An earlier observation of hippocampalalterations of apamin-senitive K⁺ channels in AD brains (as measured byapamin binding) provides additional support for the suggestion that K⁺channels may be pathophysiologically relevant in AD (Ikeda et al.,1991). Furthermore, protein kinase C (PKC) exhibits parallel changes inperipheral and brain tissues of AD patients. The levels and/or activityof this enzyme(s) were introduced in brains and fibroblasts from ADpatients (Code et al., 1988; Van Huynh et al., 1989; Govoni et al.,1993; Wang et al., 1994). Studies using immunoblotting analyses haverevealed that of the various PKC isozymes, primarily the α isoform wassignificantly reduced in fibroblasts (Govoni et al., 1996), while both αand β isoforms are reduced in brains of AD patients (Shimohama et al.,1993; Masliah et al., 1990). These brain PKC alterations might be anearly event in the disease process (Masliah et al., 1991). It is alsointeresting to note that PKC activation appears to favornonamyloidogenic processing of the amyloid precursor protein, APP(Bauxbaum et al., 1990; Gillespie et al., 1992; Selkoe, 1994; Gandy &Greengard, 1994; Bergamashi et al., 1995; Desdoutis et al., 1996;Efhimiopoulus et al., 1996). Thus, both PKC and K⁺ channel alterationscoexist in AD, with peripheral and brain expression in AD.

The line between PKC and K⁺ channel alterations has been investigationbecause PKC is known to regulate ion channels, including K⁺ channels andthat a defective PKC leads to defective K⁺ channels. This is importantnot only for the modulation of APP, but also for the role PKC and K⁺channels plays in memory establishment and recall. (e.g., see Alkon etal., 1988; Covarrubias et al., 1994; Hu et al., 1996) AD fibroblastshave been used to demonstrate both K⁺ channels and PKC defects(Etcheberrigaray et al., 1993; Govoni et al., 1993, 1996). Studies alsoshow, fibroblasts with known dysfunctional K⁺ channels treated with PKCactivators restore channel activity as monitored by the presence/absenceof TEA-induced calcium elevations. Further, assays based ontetraethylammonium chloride (TEA)-induced [Ca²⁺] elevation have beenused to show functional 113 pS K⁺ channels that are susceptible to TEAblockade (Etcheberrigaray et al., 1993, 1994; Hirashima et al., 1996).Thus, TEA-induced [Ca²⁺] elevations and K⁺ channel activity observed infibroblasts from control individuals are virtually absent in fibroblastsfrom AD patients (Etcheberrigaray et al., 1993; Hirashima et al., 1996).These studies demonstrate that the use of PKC activators can restore theresponsiveness of AD fibroblast cell lines to the TEA challenge.Further, immunoblot evidence from these studies demonstrate that thisrestoration is related to a preferential participation of the a isoform.

The present inventors have also observed that activation of proteinkinase C favors the a-secretase processing of the Alzheimer's disease(AD) amyloid precursor protein (APP), resulting in the generation ofnon-amyloidogenic soluble APP (sAPP). Consequently, the relativesecretion of amyloidogenic A₁₋₄₀ and A₁₋₄₂₍₃₎ is reduced. This isparticularly relevant since fibroblasts and other cells expressing APPand presenilin AD mutations secrete increased amounts of total Aβ and/orincreased ratios of A₁₋₄₂₍₃₎/A₁₋₄₀. Interesting, PKC defects have beenfound in AD brain (α and β isoforms) and in fibroblasts (α-isoform) fromAD patients.

Studies have shown that other PKC activators (i.e. benzolactam) withimproved selectivity for the α, β and γ isoforms enhance sAPP secretionover basal levels. The sAPP secretion in benzolactam-treated AD cellswas also slightly higher compared to control benzolactam-treatedfibroblasts, which only showed significant increases of sAPP secretionafter treatment with 10 μM BL. It was further reported thatstaurosporine (a PKC inhibitor) eliminated the effects of benzolactam inboth control and AD fibroblasts while related compounds also cause a˜3-fold sAPP secretion in PC12 cells. The present inventors have foundthat the use of bryostatin as a PKC activators to favornon-amyloidogenic APP processing is of particular therapeutic valuesince it is non-tumor promoting and already in stage II clinical trials.

Memories are thought to be a result of lasting synaptic modification inthe brain structures related to information processing. Synapses areconsidered a critical site at final targets through which memory-relatedevents realize their functional expression, whether the events involvechanged gene expression and protein translation, altered kinaseactivities, or modified signaling cascades. A few proteins have beenimplicated in associative memory including Ca²⁺/calmodulin II kinases,protein kinase C, calexcitin, a 22-kDa learning-associated Ca²⁺ bindingprotein, and type II ryanodine receptors. The modulation of PKC throughthe administration of macrocyclic lactones provides a mechanism toeffect synaptic modification.

The area of memory and learning impairment is rich in animal models thatare able to demonstrate different features of memory and learningprocesses. (See, for example, Hollister, L. E., 1990, Pharmacopsychiat.,23, (Suppl II) 33-36). The available animal models of memory loss andimpaired learning involve measuring the ability of animals to remember adiscrete event. These tests include the Morris Water Maze and thepassive avoidance procedure. In the Morris Water Maze, animals areallowed to swim in a tank divided into four quadrants, only one of whichhas a safety platform beneath the water. The platform is removed and theanimals are tested for how long they search the correct quadrant versethe incorrect quadrants. In the passive avoidance procedure the animalremembers the distinctive environment in which a mild electric shock isdelivered and avoids it on a second occasion. A variant of the passiveavoidance procedure makes use of a rodent's preference for dark enclosedenvironments over light open ones. Further discussion can be found inCrawley, J. N., 1981, Pharmacol. Biochem. Behav., 15, 695-699; Costall,B. et al, 1987, Neuropharmacol., 26, 195-200; Costall, B. et al., 1989,Pharmacol. Biochem. Behav., 32, 777-785; Barnes, J. M. et al., 1989, Br.J. Pharmacol., 98 (Suppl) 693P; Barnes, J. M. et al., 1990, Pharmacol.Biochem. Behav., 35, 955-962.

The use of the word, “normal” is meant to include individuals who havenot been diagnosed with or currently display diminished or otherwiseimpaired cognitive function. The different cognitive abilities may betested and evaluated through known means well established in the art,including but not limited to tests from basic motor-spatial skills tomore complex memory recall testing. Non-limiting examples of tests usedfor cognitive ability for non-primates include the Morris Water Maze,Radial Maze, T Maze, Eye Blink Conditioning, Delayed Recall, and CuedRecall while for primate subjects test may include Eye Blink, DelayedRecall, Cued Recall, Face Recognition, Minimental, and ADAS-Cog. Many ofthese tests are typically used in the mental state assessment forpatients suffering from AD. Similarly, the evaluation for animal modelsfor similar purposes with well describe in the literature.

Of particular interest are macrocyclic lactones (i.e. bryostatin classand neristatin class) that act to stimulate PKC. Of the bryostatin classcompounds, bryostatin-1 has been shown to activate PKC and proven to bedevoid of tumor promotion activity. Bryostatin-1, as a PKC activator, isalso particularly useful since the dose response curve of bryostatin-1is biphasic. Additionally, bryostatin-1 demonstrates differentialregulation of PKC isozymes, including PKCα, PKCδ, and PKCε. Bryostatin-1has undergone toxicity and safety studies in animals and humans and isactively being investigated as an anti-cancer agent. Bryostatin-1's usein the studies has determined that the main adverse reaction in humansis myalgia, limiting the maximum dose to 40 mg/m². The present inventionhas utilized concentrations of 0.1 nM of bryostatin-1 to cause adramatic increase of sAPP secretion. Bryostatin-1 has been compared to avehicle alone and to another PKC activator, benzolactam (BL), used at aconcentration 10,000 times higher. Also, bryostatin used at 0.01 nMstill proved effective to increase sAPP secretion. (See FIG. 1).Translocation of PKC to the cell membrane, a measure of PKC activation,demonstrates that activation is maximal at 30 min, followed by a partialdecline, which remains higher than basal translocation levels up to sixhours. (See, FIGS. 2, 3, & 7). The use of the PKC inhibitor staurosporincompletely prevents the effect of bryostatin on sAPP secretion. The datafurther demonstrates that PKC activation mediates the effect ofbryostatin on sAPP secretion. (See, FIGS. 1-3)

Macrocyclic lactones, and particularly bryostatin-1 is described in U.S.Pat. 4,560,774 (incorporated herein by reference in its entirety).Macrocyclic lactones and their derivatives are described elsewhere inthe art for instance in U.S. Pat. No. 6,187,568, U.S. Pat. No.6,043,270, U.S. Pat. No. 5,393,897, U.S. Pat. No. 5,072,004, U.S. Pat.No. 5,196,447, U.S. Pat. No. 4,833,257, and U.S. Pat. No. 4,611,066(each of which are incorporated herein by reference in theirentireties). The above patents describe various compounds and varioususes for macrocyclic lactones including their use as ananti-inflammatory or anti-tumor agent. Other discussions regardingbryostatin class compounds can be found in: Szallasi et al. (1994)Differential Regulation of Protein Kinase C Isozymes by Bryostatin 1 andPhorbol 12-Myristate 13-Acetate in NIH 3T3 Fibroblasts, Journal ofBiological Chemistry 269(3): 2118-24; Zhang et al. (1996) PreclinicalPharmacology of the Natural Product Anticancer Agent Bryostatin 1, anActivator of Protein Kinase C, Cancer Research 56: 802-808; Hennings etal. (1987) Bryostatin 1, an activator of protein kinase C, inhibitstumor promotion by phorbol esters in SENCAR mouse skin, Carcinogenesis8(9): 1343-46; Varterasian et al. (2000) Phase II Trial of Bryostatin 1in Patients with Relapse Low-Grade Non-Hodgkin's Lymphoma and ChronicLymphocytic Leukemia, Clinical Cancer Research 6: 825-28; and Mutter etal. (2000) Review Article: Chemistry and Clinical Biology of theBryostatins, Bioorganic & Medicinal Chemistry 8: 1841-1860 (each ofwhich is incorporated herein by reference in its entirety).

Myalgia is the primary side effect that limits the tolerable dose of aPKC activator. For example, in phase II clinical trials usingbryostatin-1, myalgia was reported in 10 to 87% of all treated patients.(Clamp et al. (2002) Anti-Cancer Drugs 13: 673-683). Doses of 20 μg/m²once per week for 3 weeks were well tolerated and were not associatedwith myalgia or other side effects. (Weitman et al. (1999) ClinicalCancer Research 5: 2344-2348). In another clinical study, 25 μg/m² ofbryostatin-1 administered once per week for 8 weeks was the maximumtolerated dose. (Jayson et al. (1995) British J. of Cancer 72(2):461-468). Another study reported that 50 μg/m² (a 1 hour i.v. infusionadministered once every 2 weeks for a period of 6 weeks) was themaximum-tolerated dose. (Prendville et al. (1993) British J. of Cancer68(2): 418-424). The reported myalgia was cumulative with repeatedtreatments of bryostatin-1 and developed several days after initialinfusion. Id. The deleterious effect of myalgia on a patient's qualityof life was a contributory reason for the discontinuation ofbryostatin-1 treatment. Id. The etiology of bryostatin-induced myalgiais uncertain. Id.

The National Cancer Institute has established common toxicity criteriafor grading myalgia. Specifically, the criteria are divided into fivecategories or grades. Grade 0 is no myalgia. Grade 1 myalgia ischaracterized by mild, brief pain that does not require analgesic drugs.In Grade 1 myalgia, the patient is fully ambulatory. Grade 2 myalgia ischaracterized by moderate pain, wherein the pain or required analgesicsinterfere with some functions, but do not interfere with the activitiesof daily living. Grade 3 myalgia is associated with severe pain, whereinthe pain or necessary analgesics severely interfere with the activitiesof daily living. Grade 4 myalgia is disabling.

The compositions of the present invention increase the tolerable dose ofthe PKC activator administered to a patient and/or ameliorate the sideeffects associated with PKC activation by attenuating the activation ofPKC in peripheral tissues. Specifically, PKC inhibitors inhibit PKC inperipheral tissues or preferentially inhibit PKC in peripheral tissues.Vitamin E, for example, has been shown to normalizediacylglycerol-protein kinase C activation in the aorta of diabetic ratsand cultured rat smooth muscle cells exposed to elevated glucose levels.(Kunisaki et al. (1994) Diabetes 43(11): 1372-1377). In a double-blindtrial of vitamin E (2000 IU/day) treatment in patients suffering frommoderately advanced Alzheimer's Disease, it was found that vitamin Etreatment reduced mortality and morbidity, but did not enhance cognitiveabilities. (Burke et al. (1999) Post Graduate Medicine 106(5): 85-96).

Macrocyclic lactones, including the bryostatin class, represent knowncompounds, originally derived from Bigula neritina L. While multipleuses for macrocyclic lactones, particularly the bryostatin class areknown, the relationship between macrocyclic lactones and cognitionenhancement was previously unknown.

The examples of the compounds that may be used in the present inventioninclude macrocyclic lactones (i.e. bryostatin class and neristatin classcompounds). While specific embodiments of these compounds are describedin the examples and detailed description, it should be understood thatthe compounds disclosed in the references and derivatives thereof couldalso be used for the present compositions and methods.

As will also be appreciated by one of ordinary skill in the art,macrocyclic lactone compounds and their derivatives, particularly thebryostatin class, are amenable to combinatorial synthetic techniques andthus libraries of the compounds can be generated to optimizepharmacological parameters, including, but not limited to efficacy andsafety of the compositions. Additionally, these libraries can be assayedto determine those members that preferably modulate α-secretase and/orPKC.

Combinatorial libraries high throughput screening of natural productsand fermentation broths has resulted in the discovery of several newdrugs. At present, generation and screening of chemical diversity isbeing utilized extensively as a major technique for the discovery oflead compounds, and this is certainly a major fundamental advance in thearea of drug discovery. Additionally, even after a “lead compound hasbeen identified, combinatorial techniques provide for a valuable toolfor the optimization of desired biological activity. As will beappreciated, the subject reactions readily lend themselves to thecreation of combinatorial libraries of compounds for the screening ofpharmaceutical, or other biological or medically-related activity ormaterial-related qualities. A combinatorial library for the purposes ofthe present invention is a mixture of chemically related compounds,which may be screened together for a desired property; said librariesmay be in solution or covalently linked to a solid support. Thepreparation of many related compounds in a single reaction greatlyreduces and simplifies the number of screening processes that need to becarried out. Screening for the appropriate biological property may bedone by conventional methods. Thus, the present invention also providesmethods for determining the ability of one or more inventive compoundsto bind to effectively modulate a-secretase and/or PKC.

A variety of techniques are available in the art of generatingcombinatorial libraries described below, but it will be understood thatthe present invention is not intended to be limited by the foregoingexamples and descriptions. See, for example, Blondelle et al. (1995)Trends Anal. Chem. 14:83; the Affymax U.S. Pat. Nos. 5,359,115 and5,362,899: the Ellman U.S. Pat. No. 5,288,514: the Still et al. PCTpublication WO 94/08051; Chen et al. (1994) JACS1 1 6:266 1: Kerr et al.(1993) JACS I 1 5:252; PCT publications W092/10092, WO93109668 andWO91/07087; and the Lerner et al. PCT publication WO93/20242).Accordingly, a variety of libraries on the order of about 16 to1,000,000 or more diversomers can be synthesized and screened for aparticular activity or property.

The present compounds can be administered by a variety of routes and ina variety of dosage forms including those for oral, rectal, parenteral(such as subcutaneous, intramuscular and intravenous), epidural,intrathecal, intra-articular, topical and buccal administration. Thedose range for adult human beings will depend on a number of factorsincluding the age, weight and condition of the patient and theadministration route.

For oral administration, fine powders or granules containing diluting,dispersing and/or surface-active agents may be presented in a draught,in water or a syrup, in capsules or sachets in the dry state, in anon-aqueous suspension wherein suspending agents may be included, or ina suspension in water or a syrup. Where desirable or necessary,flavoring, preserving, suspending, thickening or emulsifying agents canbe included.

Other compounds which may be included by admixture are, for example,medically inert ingredients, e.g. solid and liquid diluent, such aslactose, dextrose, saccharose, cellulose, starch or calcium phosphatefor tablets or capsules, olive oil or ethyl oleate for soft capsules andwater or vegetable oil for suspensions or emulsions; lubricating agentssuch as silica, talc, stearic acid, magnesium or calcium stearate and/orpolyethylene glycols; gelling agents such as colloidal clays; thickeningagents such as gum tragacanth or sodium alginate, binding agents such asstarches, Arabic gums, gelatin, methylcellulose, carboxymethylcelluloseor polyvinylpyrrolidone; disintegrating agents such as starch, alginicacid, alginates or sodium starch glycolate; effervescing mixtures;dyestuff; sweeteners; wetting agents such as lecithin, polysorbates orlaurylsuphates; and other therapeutically acceptable accessoryingredients, such as humectants, preservatives, buffers andantioxidants, which are known additives for such formulations.

Liquid dispersions for oral administration may be syrups, emulsions orsuspensions. The syrups may contain as carrier, for example, saccharoseor saccharose with glycerol and/or mannitol and/or sorbitol. Inparticular a syrup for diabetic patient can contain as carriers onlyproducts, for example sorbitol, which do not metabolize to glucose orwhich metabolize only a very small amount to glucose. The suspensionsand the emulsions may contain a carrier, for example a natural gum,agar, sodium alginate, pectin, methylcellulose, carboxymethylcelluloseor polyvinyl alcohol.

Suspension or solutions for intramuscular injection may contain,together with the active compound, a pharmaceutically acceptable carriersuch as sterile water, olive oil, ethyl oleate, glycols such aspropylene glycol and, if desired, a suitable amount of lidocainehydrochloride. Solutions for intravenous injection or infusion maycontain a carrier, for example, sterile water that is generally Waterfor Injection. Preferably, however, they may take the form of a sterile,aqueous, isotonic saline solution. Alternatively, the present compoundsmay be encapsulated within liposomes. The present compounds may alsoutilize other known active agent delivery systems.

The present compounds may also be administered in pure form unassociatedwith other additives, in which case a capsule, sachet or tablet is thepreferred dosage form.

Tablets and other forms of presentation provided in discrete unitsconveniently contain a daily dose, or an appropriate fraction thereof,of one of the present compounds. For example, units may contain from 5mg to 500 mg, but more usually from 10 mg to 250 mg, of one of thepresent compounds.

It will be appreciated that the pharmacological activity of thecompositions of the invention can be demonstrated using standardpharmacological models that are known in the art. Furthermore, it willbe appreciated that the inventive compositions can be incorporated orencapsulated in a suitable polymer matrix or membrane for site-specificdelivery, or can be functionalized with specific targeting agents,capable of effecting site specific delivery. These techniques, as wellas other drug delivery techniques are well known in the art.

All books, articles, or patents references herein are incorporated byreference to the extent not inconsistent with the present disclosure.The present invention will now be described by way of examples, whichare meant to illustrate, but not limit, the scope of the invention.

EXAMPLES Example 1 Cell Culture

Cultured skin fibroblasts were obtained from the Coriell CellRepositories and grown using the general guidelines established fortheir culture with slight modifications (Cristofalo & Carptentier, 1988;Hirashima et al., 1996). The culture medium in which cells were grownwas Dulbecco's modified Eagle's medium (GIBCO) supplemented with 10%calf serum (Biofluids, Inc.). Fibroblasts from control cell lines (AC),cases AG07141 and AG06241, and a familial AD (FAD) case (AG06848) wereutilized.

Example 2 PKC Activators

The different tissue distributions, the apparently distinctive roles ofdifferent isozymes, and the differential involvement in pathology makeit important to use pharmacological tools that are capable ofpreferentially targeting specific isozymes (Kozikowski et al., 1997;Hofmann, 1997). Resent research in the medicinal chemistry field hasresulted in the development of several PKC activators, for instancedifferent benzolactams and pyrollidinones. However, the currentlystudied bryostatin PKC activator not only has the benefit of providingisospecific activity, but also does not suffer from the set back of thepreviously used PKC activator, such as being tumor promoting. Thebryostatin competes for the regulatory domain of PKC and engages in veryspecific hydrogen bond interactions within this site. Additionalinformation on the organic chemistry and molecular modeling of thiscompound can be found throughout the literature.

Example 3 Treatment

Cells grown to confluence in 6 cm Petri dishes for 5-7 days. On the dayof the experiment, medium was replaced with DMEM without serum and leftundisturbed for 2 h. Upon completion of the 2 hour serum deprivation,treatment was achieved by direct application to the medium of Bryo, BLand DMSO at the appropriate concentrations. DMSO was less than 1% in allcases. In most cases, medium was collected and processed after 3 hoursof treatment for sAPP secretion. Other time points were also used toestablish a time course of secretion.

Example 4 Immunoblot Assay

Immunoblot experiments were conducted using well-established procedures(Dunbar, 1994). Cells were grown to confluency (˜90%) in 6 cm Petridishes. Levels of isozyme in response to treatment with 0.1 nMbryostatin-1 for 5, 30, 60 and 120 minutes was quantified usingprocedures slightly modified from that established by Racchi et al.,(1994). Fibroblasts were washed twice with ice-cold PBS, scraped in PBS,and collected by low-speed centrifugation. The pellets were re-suspendedin the following homogenization buffer: 20 mM Tris-HCl, pH 7.5, 2 mMEDTA, 2 mM EGTA, 5 mM DTT, 0.32 M sucrose, and protease inhibitorcocktail (Sigma). Hemogenates were obtained by sonication, andcentrifuged at ˜12,00 g for 20 minutes, and the supernatants were usedas the cytosolic fraction. The pellets were homogenized in the samebuffer containing 1.0% Triton X-100, incubated in ice for 45 minutes,and centrifuged at ˜12,000 g for 20 minutes. The supernatant from thisbatch was used as the membranous fraction. After protein determination,20 μg of protein were diluted in 2× electrophoresis sample buffer(Novex), boiled for 5 minutes, run on 10% acrylamide gel, andtransferred electrophoretically to a PVDF membrane. The membrane wassaturated with 5% milk blocker by incubating it at room temperature foran hour. The primary antibody for PKC isoform (TransductionLaboratories) was diluted (1:1000) in blocking solution and incubatedwith the membrane overnight at 4° C. After incubation with the secondaryantibody, alkaline phosphatase anti-mouse IgG (Vector Laboratories), themembrane was developed using a chemoluminescent substrate (VectorLaboratories) per the manufacturer's instructions. The band intensitieswere quantified by densitometry using a BioRad GS-800 calibratedscanning densitometer and Multianalyst software (BioRad).

Example 5 sAPP Determinations

The concentration of secreted APP was measured using conventionalimmunoblotting techniques, with minor modifications the protocol.Precipitated protein extracts each dish/treatment were loaded to freshlyprepared 10% acrylamide Tris HCl minigels and separated SDS-PAGE. Thevolume of sample loaded was corrected for total cell protein per dish.Proteins were then electrophoretically transferred to PVDF membranes.Membranes were saturated with 5% non-fat dry milk to block non-specificbinding. Blocked membranes were incubated overnight at 4° C. with thecommercially available antibody 6E10 (1:500), which recognizessAPP-alpha in the conditioned medium (SENETEK). After washing, themembranes were incubated at room temperature with horseradish peroxidaseconjugated anti-mouse IgG secondary antibody (Jackson's Laboratories).The signal was then detected using enhanced chemiluminescence followedby exposure of Hyperfilm ECL (Amersham). The band intensities werequantitative by densitometry using a BioRad GS-800 calibrated scanningdensitometer and Multianalyst software (BioRad).

As shown in FIG. 7, Bryostatin-1 elicits a powerful response,demonstrating the activation of PKC. It should be noted the activationof PKC is easily detectable 30 minutes after delivery, following a doseof only 0.1 nM of bryostatin-1.

It is also interesting to consider the data in relation to APPmetabolism and the effects of its sub-products. Studies havedemonstrated that PKC activation increases the amount of ratio ofnon-amyloidogenic (soluble APP, presumably product of the secretase) vs.amyloidogenic (Aβ1-40 and/or Aβ1-42) secreted fragments (Buxbaum et al.,1990; Gillespie et al., 1992; Selkoe, 1994). Without wishing to be heldto this theory, one could speculate that AD cells with low PKC wouldhave an impaired secretion of sAPP and/or have increased proportion ofamyloidogenic fragments. Indeed, there is evidence that some AD celllines exhibit both defective PKC and impaired sAPP secretion(Bergamaschi et al., 1995; Govoni et al., 1996). In addition, β-amyloidhas been shown to induce an AD-like K⁺ channel defect in fibroblasts(Etcheberrigaray et al., 1994) and to block K⁺ currents in culturedneurons (Good et al., 1996). Therefore, we suggest a mechanistic linksuch that an isozyme-specific PKC defect may lead to abnormal APPprocessing that, among other possible deleterious effects, alters K⁺channel function. Recent preliminary data also suggest that, perhaps ina vicious cyclical manner, β-amyloid in turn causes reductions of PKC(Favit et al., 1997).

In summary, the data suggest that the strategy to up-regulate PKCfunction targeting specific isozymes increases sAPP production. Thesestudies and such a fibroblasts model could be expanded and used as toolsto monitor the effect of compounds (bryostatin, for example) that alterpotential underlying pathological processes. Further, one of ordinaryskill in the art would know how to further tests these samples throughCa²⁺ imagining and electrophysiology. Such compounds could then be usedas bases for rational design of pharmacological agents for thisdisorder.

Example 6 Morris Water Maze

The effect of PKC activators on cognition was demonstrated by the MorrisWater Maze paradigm. In the present example, rats were injectedintraventricularly with bryostatin-1 and trained for 4 days (followingstandard protocols). Retention was assessed on the 5^(th) day. Learningwas measured as the reduction of escape latency from trial to trail,which was significantly lower in the treated animals. Acquisition ofmemory was measured as time spent in the relevant quadrant (5^(th) day).Memory or retention was significantly enhanced, in treated animals,compared to sham injection animals (see, FIGS. 4 through 5(a)-5(c)). Therats treated with bryostatin-1 showed improved cognition compared tocontrol rats within 2 days of treatment. (See, FIG. 4). Bryostatin iscapable of being used at concentrations to improve cognition that are300 to 300,000 times lower than the concentration used to treat tumors.The above example further shows that cognitive ability can be improvedin non-diseased subjects as compared to other non-diseased subjectsthrough the administration of bryostatin-1.

Because of the previously conducted safety, toxicology and phase IIclinical studies for cancer, one can conclude that the use of PKCactivators, particularly bryostatin-1, would be viewed as safe and thatphase II studies for AD treatment/cognitive enhancement could beexpedited. Furthermore, bryostatin-1's lipophilic nature providesincreased blood brain barrier transport. The present invention wouldallow for intravenous, oral, intraventricullar, and other known methodsfor administration.

Test of sAPP secretion experiments, PKC activation experiments, andanimal behavior experiments have shown that increases in sAPP secretionfollow increased PKC activation and result in improved cognition inanimal behavior studies.

1. A composition comprising: a) a PKC activator; b) a PKC inhibitor; andc) a pharmaceutically acceptable carrier.
 2. The composition of claim 1,wherein the PKC activator is a macrocyclic lactone.
 3. The compositionof claim 1, wherein the PKC activator is a benzolactam.
 4. Thecomposition of claim 1, wherein the PKC activator is a pyrrolidinone. 5.The composition of claim 2, wherein the bryostatin is selected from thegroup consisting of bryostatin-1, -2, -3, -4, -5, -6, -7, -8, -9, -10,-11, -12, -13, -14, -15, -16, -17, and -18.
 6. The composition of claim5, wherein the bryostatin is bryostatin-1.
 7. The composition of claim2, wherein the macrocyclic lactone is a neristatin.
 8. The compositionof claim 7, wherein the neristatin is neristatin-1.
 9. The compositionof claim 1, wherein the PKC is vitamin E.
 10. The composition of claim9, wherein the vitamin E is α-tocopherol.
 11. The composition of claim10, wherein the α-tocopherol is present in proportion of between ofbetween 15 and 2,000 IU per day.
 12. A method for reducingneurodegeneration comprising administering to a subject in need thereofthe composition of claim 1 in an amount effective to reduceneurodegeneration.
 13. A method for reducing neurodegenerationcomprising administering to a subject in need thereof the composition ofclaim 2 in an amount effective to reduce neurodegeneration.
 14. A methodfor reducing neurodegeneration comprising administering to a subject inneed thereof the composition of claim 3 in an amount effective to reduceneurodegeneration.
 15. A method for reducing neurodegenerationcomprising administering to a subject in need thereof the composition ofclaim 4 in an amount effective to reduce neurodegeneration.
 16. A methodfor reducing neurodegeneration comprising administering to a subject inneed thereof the composition of claim 5 in an amount effective to reduceneurodegeneration.
 17. A method for reducing neurodegenerationcomprising administering to a subject in need thereof the composition ofclaim 6 in an amount effective to reduce neurodegeneration.
 18. A methodfor reducing neurodegeneration comprising administering to a subject inneed thereof the composition of claim 7 in an amount effective to reduceneurodegeneration.
 19. A method for reducing neurodegenerationcomprising administering to a subject in need thereof the composition ofclaim 8 in an amount effective to reduce neurodegeneration.
 20. A methodfor reducing neurodegeneration comprising administering to a subject inneed thereof the composition of claim 9 in an amount effective to reduceneurodegeneration.
 21. A method for reducing neurodegenerationcomprising administering to a subject in need thereof the composition ofclaim 10 in an amount effective to reduce neurodegeneration.
 22. Amethod for reducing neurodegeneration comprising administering to asubject in need thereof the composition of claim 11 in an amounteffective to reduce neurodegeneration.
 23. The method of claim 22,wherein the subject suffers from a neurodegenerative disease selectedfrom the group consisting of Alzheimer's Disease; multi-infarctdementia; the Lewy-body variant of Alzheimer's Disease with or withoutassociation with Parkinson's disease; Creutzfeld-Jakob disease;Korsakoff's disorder; and attention deficit hyperactivity disorder. 24.The method of claim 23, wherein the neurodegenerative disease isAlzheimer's Disease.
 25. A method for reducing loss of cognitive abilitycomprising administering to a subject in need thereof the composition ofclaim 1 in an amount effective to reduce loss of cognitive ability. 26.A method for reducing loss of cognitive ability comprising administeringto a subject in need thereof the composition of claim 2 in an amounteffective to reduce loss of cognitive ability.
 27. A method for reducingloss of cognitive ability comprising administering to a subject in needthereof the composition of claim 3 in an amount effective to reduce lossof cognitive ability.
 28. A method for reducing loss of cognitiveability comprising administering to a subject in need thereof thecomposition of claim 4 in an amount effective to reduce loss ofcognitive ability.
 29. A method for reducing loss of cognitive abilitycomprising administering to a subject in need thereof the composition ofclaim 5 in an amount effective to reduce loss of cognitive ability. 30.A method for reducing loss of cognitive ability comprising administeringto a subject in need thereof the composition of claim 6 in an amounteffective to reduce loss of cognitive ability.
 31. A method for reducingloss of cognitive ability comprising administering to a subject in needthereof the composition of claim 7 in an amount effective to reduce lossof cognitive ability.
 32. A method for reducing loss of cognitiveability comprising administering to a subject in need thereof thecomposition of claim 8 in an amount effective to reduce loss ofcognitive ability.
 33. A method for reducing loss of cognitive abilitycomprising administering to a subject in need thereof the composition ofclaim 9 in an amount effective to reduce loss of cognitive ability. 34.A method for reducing loss of cognitive ability comprising administeringto a subject in need thereof the composition of claim 10 in an amounteffective to reduce loss of cognitive ability.
 35. A method for reducingloss of cognitive ability comprising administering to a subject in needthereof the composition of claim 11 in an amount effective to reduceloss of cognitive ability.
 36. The method of claim 25, wherein thesubject suffers from a neurodegenerative disease selected from the groupconsisting of Alzheimer's Disease; multi-infarct dementia; the Lewy-bodyvariant of Alzheimer's Disease with or without association withParkinson's disease; Creutzfeld-Jakob disease; Korsakoff's disorder; andattention deficit hyperactivity disorder.
 37. The method of claim 25,wherein the neurodegenerative disease is Alzheimer's Disease.
 38. Themethod of claim 25, wherein the cognitive ability is selected from thegroup consisting of learning, memory and attention.
 39. A method forenhancing cognitive ability comprising administering to a subject inneed thereof the composition of claim 1 in an amount effective toenhance cognitive ability.
 40. A method for enhancing cognitive abilitycomprising administering to a subject in need thereof the composition ofclaim 2 in an amount effective to enhance cognitive ability.
 41. Amethod for enhancing cognitive ability comprising administering to asubject in need thereof the composition of claim 3 in an amounteffective to enhance cognitive ability.
 42. A method for enhancingcognitive ability comprising administering to a subject in need thereofthe composition of claim 4 in an amount effective to enhance cognitiveability.
 43. A method for enhancing cognitive ability comprisingadministering to a subject in need thereof the composition of claim 5 inan amount effective to enhance cognitive ability.
 44. A method forenhancing cognitive ability comprising administering to a subject inneed thereof the composition of claim 6 in an amount effective toenhance cognitive ability.
 45. A method for enhancing cognitive abilitycomprising administering to a subject in need thereof the composition ofclaim 7 in an amount effective to enhance cognitive ability.
 46. Amethod for enhancing cognitive ability comprising administering to asubject in need thereof the composition of claim 8 in an amounteffective to enhance cognitive ability.
 47. A method for enhancingcognitive ability comprising administering to a subject in need thereofthe composition of claim 9 in an amount effective to enhance cognitiveability.
 48. A method for enhancing cognitive ability comprisingadministering to a subject in need thereof the composition of claim 10in an amount effective to enhance cognitive ability.
 49. A method forenhancing cognitive ability comprising administering to a subject inneed thereof the composition of claim 11 in an amount effective toenhance cognitive ability.
 50. The method of claim 39, wherein thesubject suffers from a neurodegenerative disease selected from the groupconsisting of Alzheimer's Disease; multi-infarct dementia; the Lewy-bodyvariant of Alzheimer's Disease with or without association withParkinson's disease; Creutzfeld-Jakob disease; Korsakoff's disorder; andattention deficit hyperactivity disorder.
 51. The method of claim 39,wherein the neurodegenerative disease is Alzheimer's Disease.
 52. Themethod of claim 39, wherein the cognitive ability is selected from thegroup consisting of learning, memory and attention.
 53. A method forreducing loss of cognitive ability comprising the steps of administeringto a subject in need thereof a) a PKC activator with or without apharmaceutically acceptable carrier; and b) a PKC inhibitor with orwithout a pharmaceutically acceptable carrier; wherein the PKC activatoris administered in an amount effective to reduce loss of cognitiveability.
 54. The method of claim 53, wherein the PKC activator and PKCinhibitor are administered simultaneously.
 55. The method of claim 53,wherein the PKC activator is administered prior to administration of thePKC inhibitor.
 56. The method of claim 53, wherein the PKC inhibitor isadministered prior to administration of the PKC activator.
 57. A methodfor enhancing cognitive ability comprising the steps of administering toa subject in need thereof a) a PKC activator with or without apharmaceutically acceptable carrier; and b) a PKC inhibitor with orwithout a pharmaceutically acceptable carrier; wherein the PKC activatoris administered in an amount effective to enhance cognitive ability. 58.The method of claim 57, wherein the PKC activator and PKC inhibitor isadministered simultaneously.
 59. The method of claim 57, wherein the PKCactivator is administered prior to administration of the PKC inhibitor.60. The method of claim 57, wherein the PKC inhibitor is administeredprior to administration of the PKC activator.
 61. A method for reducingneurodegeneration comprising the steps of administering to a subject inneed thereof a) a PKC activator with or without a pharmaceuticallyacceptable carrier; and b) a PKC inhibitor with or without apharmaceutically acceptable carrier; wherein the PKC activator isadministered in an amount effective to reduce neurodegeneration.
 62. Themethod of claim 61, wherein the PKC activator and PKC inhibitor isadministered simultaneously.
 63. The method of claim 61, wherein the PKCactivator is administered prior to administration of the PKC inhibitor.64. The method of claim 61, wherein the PKC inhibitor is administeredprior to administration of the PKC activator.
 65. The method of claim61, wherein the PKC activator is a macrocyclic lactone.
 66. The methodof claim 61, wherein the PKC activator is a benzolactam.
 67. The methodof claim 61, wherein the PKC activator is a pyrrolidinone.
 68. Thecomposition of claim 61, wherein the macrocyclic lactone is selectedfrom the group consisting of bryostatin-1, -2, -3, -4, -5, -6, -7, -8,-9, -10, -11, -12, -13, -14, -15, -16, -17, and -18.
 69. The compositionof claim 68, wherein the bryostatin is bryostatin-1.
 70. The compositionof claim 61, wherein the macrocyclic lactone is a neristatin.
 71. Thecomposition of claim 70, wherein the neristatin is neristatin-1.
 72. Thecomposition of claim 61, wherein the vitamin E is in an amount between15 and 2000 IU per day.